docs: def add_field(self, name, script, lang=None, params=None, ignore_failure=False):
          """
          Add a field to script_fields
          """
          data = {}
          if lang:
              data["lang"] = lang
  
          if script:
              data['script'] = script
          else:
              raise ScriptFieldsError("Script is required for script_fields definition")
          if params:
              if isinstance(params, dict):
                  if len(params):
                      data['params'] = params
              else:
                  raise ScriptFieldsError("Parameters should be a valid dictionary")
          if ignore_failure:
              data['ignore_failure'] = ignore_failure
          self.fields[name] = data